High- and low-viscosity estolide base oils and lubricants

ABSTRACT

Provided herein are compounds of the formula: 
                         
in which n is an integer equal to or greater than 1; R 2  is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R 1 , R 3 , and R 4 , independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched, wherein compositions comprising the compounds are characterized by particular combinations of values for estolide number, kinematic viscosity, and pour point. Also provided are compositions containing the compounds and methods of making both the compounds and compositions thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 61/378,891, filed Aug. 31, 2010, andU.S. Provisional Patent Application No. 61/498,499, filed Jun. 17, 2011,both of which are incorporated herein by reference in their entiretiesfor all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

The subject of this invention was made with support under U.S.Department of Agriculture—Agricultural Research Service CooperativeResearch and Development Agreement (CRADA) Nos. 58-3K95-1-1508-M and58-3K95-6-1147. Accordingly, the government may have certain rights inthis invention.

FIELD

The present disclosure relates to high- and low-viscosity base oilstocks and lubricants and methods of making the same. The estolidesdescribed herein may be suitable for use as biodegradable base oilstocks and lubricants.

BACKGROUND

Synthetic esters such as polyol esters and adipates, low viscosity polyalpha olefins (PAO) such as PAO 2, and vegetable oils such as canola oiland oleates have been described for use industrially as biodegradablebase stocks to formulate lubricants. Such base stocks may be used in theproduction of lubricating oils for automotives, industrial lubricants,and lubricating greases. Finished lubricants typically comprise the baseoil and additives to help achieve desired viscometric properties, lowtemperature behavior, oxidative stability, corrosion protection,demulsibility and water rejection, friction coefficients, lubricities,wear protection, air release, color and other properties. However, it isgenerally understood that biodegradability cannot be improved by usingcommon additives that are available in today's marketplace. Forenvironmental, economical, and regulatory reasons, it is of interest toproduce biodegradable lubricating oils, other biodegradable lubricants,and compositions including lubricating oils and/or lubricants, fromrenewable sources of biological origin.

Estolides present a potential source of biobased, biodegradable oilsthat may be useful as lubricants and base stocks. Several estolidesynthetic processes have been previously described, such as thehomopolymerization of castor oil fatty acids or 12-hydroxystearic acidunder thermal or acid catalyzed conditions, as well as the production ofestolides from unsaturated fatty acids using a high temperature andpressure condensation over clay catalysts. Processes for the enzymaticproduction of estolides from hydroxy fatty acids present in castor oilusing lipase have also been described.

In U.S. Pat. No. 6,018,063, Isbell et al. described estolide compoundsderived from oleic acids under acidic conditions and having propertiesfor use as lubricant base stocks, wherein the “capping” fatty acidcomprises oleic or stearic acid. In U.S. Pat. No. 6,316,649, Cermak etal. reported estolides derived from oleic acids and having cappingmaterials derived from C₆ to C₁₄ fatty acids. According to Cermak etal., larger capping materials such as stearic acid adversely affect theproperties of the estolide, such that having a greater percentage ofstearic acid as the capping moiety generally increases pour pointtemperatures.

SUMMARY

Described herein are estolide compounds, estolide-containingcompositions, and methods of making the same. In certain embodiments,such compounds and/or compositions may be useful as base oils andlubricants.

In certain embodiments, the estolides comprise at least one compound ofFormula I:

-   -   wherein    -   x is, independently for each occurrence, an integer selected        from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,        17, 18, 19, and 20;    -   y is, independently for each occurrence, an integer selected        from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,        17, 18, 19, and 20;    -   n is an integer selected from 0 to 12;    -   R₁ is an optionally substituted alkyl that is saturated or        unsaturated, and branched or unbranched; and    -   R₂ is selected from hydrogen and optionally substituted alkyl        that is saturated or unsaturated, and branched or unbranched;    -   wherein each fatty acid chain residue of said at least one        compound is independently optionally substituted; and        -   wherein said composition has:        -   an EN selected from an integer that is equal to or greater            than about 4, a kinematic viscosity equal to or greater than            about 200 cSt when measured at 40° C., and a pour point            equal to or lower than about −40° C.;        -   an EN selected from an integer or fraction of an integer            that is equal to or greater than about 3, a kinematic            viscosity equal to or greater than about 130 cSt when            measured at 40° C., and a pour point equal to or lower than            about −30° C.;        -   an EN selected from an integer or fraction of an integer            that is equal to or less than about 2, a kinematic viscosity            equal to or less than about 55 cSt when measured at 40° C.,            and a pour point equal to or lower than about −25° C.; or        -   an EN selected from an integer or fraction of an integer            that is equal to or less than about 2, a kinematic viscosity            equal to or less than about 45 cSt when measured at 40° C.,            and a pour point equal to or lower than about −25° C.

In certain embodiments, the estolide-containing compositions comprise atleast one compound of Formula II:

-   -   wherein    -   n is an integer equal to or greater than 0;    -   R₁ is an optionally substituted alkyl that is saturated or        unsaturated, and branched or unbranched; and    -   R₂ is selected from hydrogen and optionally substituted alkyl        that is saturated or unsaturated, and branched or unbranched;        and    -   R₃ and R₄, independently for each occurrence, are selected from        optionally substituted alkyl that is saturated or unsaturated,        and branched or unbranched;        -   wherein said composition has:        -   an EN selected from an integer that is equal to or greater            than about 4, a kinematic viscosity equal to or greater than            about 200 cSt when measured at 40° C., and a pour point            equal to or lower than about −40° C.;        -   an EN selected from an integer or fraction of an integer            that is equal to or greater than about 3, a kinematic            viscosity equal to or greater than about 130 cSt when            measured at 40° C., and a pour point equal to or lower than            about −30° C.;        -   an EN selected from an integer or fraction of an integer            that is equal to or less than about 2, a kinematic viscosity            equal to or less than about 55 cSt when measured at 40° C.,            and a pour point equal to or lower than about −25° C.; or        -   an EN selected from an integer or fraction of an integer            that is equal to or less than about 2, a kinematic viscosity            equal to or less than about 45 cSt when measured at 40° C.,            and a pour point equal to or lower than about −25° C.

In certain embodiments, the estolides-containing compositions compriseat least one compound represented of Formula III:

-   -   wherein    -   x is, independently for each occurrence, an integer selected        from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,        17, 18, 19, and 20;    -   y is, independently for each occurrence, an integer selected        from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,        17, 18, 19, and 20;    -   n is an integer equal to or greater than 0;    -   R₁ is an optionally substituted alkyl that is saturated or        unsaturated, and branched or unbranched; and    -   R₂ is selected from hydrogen and optionally substituted alkyl        that is saturated or unsaturated, and branched or unbranched;    -   wherein each fatty acid chain residue of said at least one        compound is independently optionally substituted; and        -   wherein said composition has:        -   an EN selected from an integer that is equal to or greater            than about 4, a kinematic viscosity equal to or greater than            about 200 cSt when measured at 40° C., and a pour point            equal to or lower than about −40° C.;        -   an EN selected from an integer or fraction of an integer            that is equal to or greater than about 3, a kinematic            viscosity equal to or greater than about 130 cSt when            measured at 40° C., and a pour point equal to or lower than            about −30° C.;        -   an EN selected from an integer or fraction of an integer            that is equal to or less than about 2, a kinematic viscosity            equal to or less than about 55 cSt when measured at 40° C.,            and a pour point equal to or lower than about −25° C.; or        -   an EN selected from an integer or fraction of an integer            that is equal to or less than about 2, a kinematic viscosity            equal to or less than about 45 cSt when measured at 40° C.,            and a pour point equal to or lower than about −25° C.

DETAILED DESCRIPTION

As used in the present specification, the following words, phrases andsymbols are generally intended to have the meanings as set forth below,except to the extent that the context in which they are used indicatesotherwise. The following abbreviations and terms have the indicatedmeanings throughout:

A dash (“-”) that is not between two letters or symbols is used toindicate a point of attachment for a substituent. For example, —C(O)NH₂is attached through the carbon atom.

“Alkoxy” by itself or as part of another substituent refers to a radical—OR³¹ where R³¹ is alkyl, cycloalkyl, cycloalkylalkyl, aryl, orarylalkyl, which can be substituted, as defined herein. In someembodiments, alkoxy groups have from 1 to 8 carbon atoms. In someembodiments, alkoxy groups have 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms.Examples of alkoxy groups include, but are not limited to, methoxy,ethoxy, propoxy, butoxy, cyclohexyloxy, and the like.

“Alkyl” by itself or as part of another substituent refers to asaturated or unsaturated, branched, or straight-chain monovalenthydrocarbon radical derived by the removal of one hydrogen atom from asingle carbon atom of a parent alkane, alkene, or alkyne. Examples ofalkyl groups include, but are not limited to, methyl; ethyls such asethanyl, ethenyl, and ethynyl; propyls such as propan-1-yl, propan-2-yl,prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl (allyl), prop-1-yn-1-yl,prop-2-yn-1-yl, etc.; butyls such as butan-1-yl, butan-2-yl,2-methyl-propan-1-yl, 2-methyl-propan-2-yl, but-1-en-1-yl,but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-2-yl,buta-1,3-dien-1-yl, buta-1,3-dien-2-yl, but-1-yn-1-yl, but-1-yn-3-yl,but-3-yn-1-yl, etc.; and the like.

Unless otherwise indicated, the term “alkyl” is specifically intended toinclude groups having any degree or level of saturation, i.e., groupshaving exclusively single carbon-carbon bonds, groups having one or moredouble carbon-carbon bonds, groups having one or more triplecarbon-carbon bonds, and groups having mixtures of single, double, andtriple carbon-carbon bonds. Where a specific level of saturation isintended, the terms “alkanyl,” “alkenyl,” and “alkynyl” are used. Incertain embodiments, an alkyl group comprises from 1 to 40 carbon atoms,in certain embodiments, from 1 to 22 or 1 to 18 carbon atoms, in certainembodiments, from 1 to 16 or 1 to 8 carbon atoms, and in certainembodiments from 1 to 6 or 1 to 3 carbon atoms. In certain embodiments,an alkyl group comprises from 8 to 22 carbon atoms, in certainembodiments, from 8 to 18 or 8 to 16. In some embodiments, the alkylgroup comprises from 3 to 20 or 7 to 17 carbons. In some embodiments,the alkyl group comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, or 22 carbon atoms.

“Aryl” by itself or as part of another substituent refers to amonovalent aromatic hydrocarbon radical derived by the removal of onehydrogen atom from a single carbon atom of a parent aromatic ringsystem. Aryl encompasses 5- and 6-membered carbocyclic aromatic rings,for example, benzene; bicyclic ring systems wherein at least one ring iscarbocyclic and aromatic, for example, naphthalene, indane, andtetralin; and tricyclic ring systems wherein at least one ring iscarbocyclic and aromatic, for example, fluorene. Aryl encompassesmultiple ring systems having at least one carbocyclic aromatic ringfused to at least one carbocyclic aromatic ring, cycloalkyl ring, orheterocycloalkyl ring. For example, aryl includes 5- and 6-memberedcarbocyclic aromatic rings fused to a 5- to 7-membered non-aromaticheterocycloalkyl ring containing one or more heteroatoms chosen from N,O, and S. For such fused, bicyclic ring systems wherein only one of therings is a carbocyclic aromatic ring, the point of attachment may be atthe carbocyclic aromatic ring or the heterocycloalkyl ring. Examples ofaryl groups include, but are not limited to, groups derived fromaceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene,benzene, chrysene, coronene, fluoranthene, fluorene, hexacene,hexaphene, hexylene, as-indacene, s-indacene, indane, indene,naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene,pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene,picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene,trinaphthalene, and the like. In certain embodiments, an aryl group cancomprise from 5 to 20 carbon atoms, and in certain embodiments, from 5to 12 carbon atoms. In certain embodiments, an aryl group can comprise5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbonatoms. Aryl, however, does not encompass or overlap in any way withheteroaryl, separately defined herein. Hence, a multiple ring system inwhich one or more carbocyclic aromatic rings is fused to aheterocycloalkyl aromatic ring, is heteroaryl, not aryl, as definedherein.

“Arylalkyl” by itself or as part of another substituent refers to anacyclic alkyl radical in which one of the hydrogen atoms bonded to acarbon atom, typically a terminal or sp³ carbon atom, is replaced withan aryl group. Examples of arylalkyl groups include, but are not limitedto, benzyl, 2-phenylethan-1-yl, 2-phenylethen-1-yl, naphthylmethyl,2-naphthylethan-1-yl, 2-naphthylethen-1-yl, naphthobenzyl,2-naphthophenylethan-1-yl, and the like. Where specific alkyl moietiesare intended, the nomenclature arylalkanyl, arylalkenyl, or arylalkynylis used. In certain embodiments, an arylalkyl group is C₇₋₃₀ arylalkyl,e.g., the alkanyl, alkenyl, or alkynyl moiety of the arylalkyl group isC₁₋₁₀ and the aryl moiety is C₆₋₂₀, and in certain embodiments, anarylalkyl group is C₇₋₂₀ arylalkyl, e.g., the alkanyl, alkenyl, oralkynyl moiety of the arylalkyl group is C₁₈ and the aryl moiety isC₆₋₁₂.

Estolide “base oil” and “base stock”, unless otherwise indicated, referto any composition comprising one or more estolide compounds. It shouldbe understood that an estolide “base oil” or “base stock” is not limitedto compositions for a particular use, and may generally refer tocompositions comprising one or more estolides, including mixtures ofestolides. Estolide base oils and base stocks can also include compoundsother than estolides.

“Compounds” refers to compounds encompassed by structural Formula I, II,and III herein and includes any specific compounds within the formulawhose structure is disclosed herein. Compounds may be identified eitherby their chemical structure and/or chemical name. When the chemicalstructure and chemical name conflict, the chemical structure isdeterminative of the identity of the compound. The compounds describedherein may contain one or more chiral centers and/or double bonds andtherefore may exist as stereoisomers such as double-bond isomers (i.e.,geometric isomers), enantiomers, or diastereomers. Accordingly, anychemical structures within the scope of the specification depicted, inwhole or in part, with a relative configuration encompass all possibleenantiomers and stereoisomers of the illustrated compounds including thestereoisomerically pure form (e.g., geometrically pure, enantiomericallypure, or diastereomerically pure) and enantiomeric and stereoisomericmixtures. Enantiomeric and stereoisomeric mixtures may be resolved intotheir component enantiomers or stereoisomers using separation techniquesor chiral synthesis techniques well known to the skilled artisan.

For the purposes of the present disclosure, “chiral compounds” arecompounds having at least one center of chirality (i.e. at least oneasymmetric atom, in particular at least one asymmetric C atom), havingan axis of chirality, a plane of chirality or a screw structure.“Achiral compounds” are compounds which are not chiral.

Compounds of Formula I, II, and III include, but are not limited to,optical isomers of compounds of Formula I, II, and III, racematesthereof, and other mixtures thereof. In such embodiments, the singleenantiomers or diastereomers, i.e., optically active forms, can beobtained by asymmetric synthesis or by resolution of the racemates.Resolution of the racemates may be accomplished by, for example,chromatography, using, for example a chiral high-pressure liquidchromatography (HPLC) column. However, unless otherwise stated, itshould be assumed that Formula I, II, and III cover all asymmetricvariants of the compounds described herein, including isomers,racemates, enantiomers, diastereomers, and other mixtures thereof. Inaddition, compounds of Formula I, II and III include Z- and E-forms(e.g., cis- and trans-forms) of compounds with double bonds. Thecompounds of Formula I, II, and III may also exist in several tautomericforms including the enol form, the keto form, and mixtures thereof.Accordingly, the chemical structures depicted herein encompass allpossible tautomeric forms of the illustrated compounds.

“Cycloalkyl” by itself or as part of another substituent refers to asaturated or unsaturated cyclic alkyl radical. Where a specific level ofsaturation is intended, the nomenclature “cycloalkanyl” or“cycloalkenyl” is used. Examples of cycloalkyl groups include, but arenot limited to, groups derived from cyclopropane, cyclobutane,cyclopentane, cyclohexane, and the like. In certain embodiments, acycloalkyl group is C₃₋₁₅ cycloalkyl, and in certain embodiments, C₃₋₁₂cycloalkyl or C₅₋₁₂ cycloalkyl. In certain embodiments, a cycloalkylgroup is a C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, or C₁₅cycloalkyl.

“Cycloalkylalkyl” by itself or as part of another substituent refers toan acyclic alkyl radical in which one of the hydrogen atoms bonded to acarbon atom, typically a terminal or sp³ carbon atom, is replaced with acycloalkyl group. Where specific alkyl moieties are intended, thenomenclature cycloalkylalkanyl, cycloalkylalkenyl, or cycloalkylalkynylis used. In certain embodiments, a cycloalkylalkyl group is C₇₋₃₀cycloalkylalkyl, e.g., the alkanyl, alkenyl, or alkynyl moiety of thecycloalkylalkyl group is C₁₋₁₀ and the cycloalkyl moiety is C₆₋₂₀, andin certain embodiments, a cycloalkylalkyl group is C₇₋₂₀cycloalkylalkyl, e.g., the alkanyl, alkenyl, or alkynyl moiety of thecycloalkylalkyl group is C₁₋₈ and the cycloalkyl moiety is C₄₋₂₀ orC₆₋₁₂.

“Halogen” refers to a fluoro, chloro, bromo, or iodo group.

“Heteroaryl” by itself or as part of another substituent refers to amonovalent heteroaromatic radical derived by the removal of one hydrogenatom from a single atom of a parent heteroaromatic ring system.Heteroaryl encompasses multiple ring systems having at least onearomatic ring fused to at least one other ring, which can be aromatic ornon-aromatic in which at least one ring atom is a heteroatom. Heteroarylencompasses 5- to 12-membered aromatic, such as 5- to 7-membered,monocyclic rings containing one or more, for example, from 1 to 4, or incertain embodiments, from 1 to 3, heteroatoms chosen from N, O, and S,with the remaining ring atoms being carbon; and bicyclicheterocycloalkyl rings containing one or more, for example, from 1 to 4,or in certain embodiments, from 1 to 3, heteroatoms chosen from N, O,and S, with the remaining ring atoms being carbon and wherein at leastone heteroatom is present in an aromatic ring. For example, heteroarylincludes a 5- to 7-membered heterocycloalkyl, aromatic ring fused to a5- to 7-membered cycloalkyl ring. For such fused, bicyclic heteroarylring systems wherein only one of the rings contains one or moreheteroatoms, the point of attachment may be at the heteroaromatic ringor the cycloalkyl ring. In certain embodiments, when the total number ofN, S, and O atoms in the heteroaryl group exceeds one, the heteroatomsare not adjacent to one another. In certain embodiments, the totalnumber of N, S, and O atoms in the heteroaryl group is not more thantwo. In certain embodiments, the total number of N, S, and O atoms inthe aromatic heterocycle is not more than one. Heteroaryl does notencompass or overlap with aryl as defined herein.

Examples of heteroaryl groups include, but are not limited to, groupsderived from acridine, arsindole, carbazole, β-carboline, chromane,chromene, cinnoline, furan, imidazole, indazole, indole, indoline,indolizine, isobenzofuran, isochromene, isoindole, isoindoline,isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole,oxazole, perimidine, phenanthridine, phenanthroline, phenazine,phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine,pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline,quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene,triazole, xanthene, and the like. In certain embodiments, a heteroarylgroup is from 5- to 20-membered heteroaryl, and in certain embodimentsfrom 5- to 12-membered heteroaryl or from 5- to 10-membered heteroaryl.In certain embodiments, a heteroaryl group is a 5-, 6-, 7-, 8-, 9-, 10-,11-, 12-, 13-, 14-, 15-, 16-, 17-, 18-, 19-, or 20-membered heteroaryl.In certain embodiments heteroaryl groups are those derived fromthiophene, pyrrole, benzothiophene, benzofuran, indole, pyridine,quinoline, imidazole, oxazole, and pyrazine.

“Heteroarylalkyl” by itself or as part of another substituent refers toan acyclic alkyl radical in which one of the hydrogen atoms bonded to acarbon atom, typically a terminal or sp³ carbon atom, is replaced with aheteroaryl group. Where specific alkyl moieties are intended, thenomenclature heteroarylalkanyl, heteroarylalkenyl, or heteroarylalkynylis used. In certain embodiments, a heteroarylalkyl group is a 6- to30-membered heteroarylalkyl, e.g., the alkanyl, alkenyl, or alkynylmoiety of the heteroarylalkyl is 1- to 10-membered and the heteroarylmoiety is a 5- to 20-membered heteroaryl, and in certain embodiments, 6-to 20-membered heteroarylalkyl, e.g., the alkanyl, alkenyl, or alkynylmoiety of the heteroarylalkyl is 1- to 8-membered and the heteroarylmoiety is a 5- to 12-membered heteroaryl.

“Heterocycloalkyl” by itself or as part of another substituent refers toa partially saturated or unsaturated cyclic alkyl radical in which oneor more carbon atoms (and any associated hydrogen atoms) areindependently replaced with the same or different heteroatom. Examplesof heteroatoms to replace the carbon atom(s) include, but are notlimited to, N, P, O, S, Si, etc. Where a specific level of saturation isintended, the nomenclature “heterocycloalkanyl” or “heterocycloalkenyl”is used. Examples of heterocycloalkyl groups include, but are notlimited to, groups derived from epoxides, azirines, thiiranes,imidazolidine, morpholine, piperazine, piperidine, pyrazolidine,pyrrolidine, quinuclidine, and the like.

“Heterocycloalkylalkyl” by itself or as part of another substituentrefers to an acyclic alkyl radical in which one of the hydrogen atomsbonded to a carbon atom, typically a terminal or sp³ carbon atom, isreplaced with a heterocycloalkyl group. Where specific alkyl moietiesare intended, the nomenclature heterocycloalkylalkanyl,heterocycloalkylalkenyl, or heterocycloalkylalkynyl is used. In certainembodiments, a heterocycloalkylalkyl group is a 6- to 30-memberedheterocycloalkylalkyl, e.g., the alkanyl, alkenyl, or alkynyl moiety ofthe heterocycloalkylalkyl is 1- to 10-membered and the heterocycloalkylmoiety is a 5- to 20-membered heterocycloalkyl, and in certainembodiments, 6- to 20-membered heterocycloalkylalkyl, e.g., the alkanyl,alkenyl, or alkynyl moiety of the heterocycloalkylalkyl is 1- to8-membered and the heterocycloalkyl moiety is a 5- to 12-memberedheterocycloalkyl.

“Mixture” refers to a collection of molecules or chemical substances.Each component in a mixture can be independently varied. A mixture maycontain, or consist essentially of, two or more substances intermingledwith or without a constant percentage composition, wherein eachcomponent may or may not retain its essential original properties, andwhere molecular phase mixing may or may not occur. In mixtures, thecomponents making up the mixture may or may not remain distinguishablefrom each other by virtue of their chemical structure.

“Parent aromatic ring system” refers to an unsaturated cyclic orpolycyclic ring system having a conjugated π (pi) electron system.Included within the definition of “parent aromatic ring system” arefused ring systems in which one or more of the rings are aromatic andone or more of the rings are saturated or unsaturated, such as, forexample, fluorene, indane, indene, phenalene, etc. Examples of parentaromatic ring systems include, but are not limited to, aceanthrylene,acenaphthylene, acephenanthrylene, anthracene, azulene, benzene,chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene,hexylene, as-indacene, s-indacene, indane, indene, naphthalene,octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene,pentalene, pentaphene, perylene, phenalene, phenanthrene, picene,pleiadene, pyrene, pyranthrene, rubicene, triphenylene, trinaphthalene,and the like.

“Parent heteroaromatic ring system” refers to a parent aromatic ringsystem in which one or more carbon atoms (and any associated hydrogenatoms) are independently replaced with the same or different heteroatom.Examples of heteroatoms to replace the carbon atoms include, but are notlimited to, N, P, O, S, Si, etc. Specifically included within thedefinition of “parent heteroaromatic ring systems” are fused ringsystems in which one or more of the rings are aromatic and one or moreof the rings are saturated or unsaturated, such as, for example,arsindole, benzodioxan, benzofuran, chromane, chromene, indole,indoline, xanthene, etc. Examples of parent heteroaromatic ring systemsinclude, but are not limited to, arsindole, carbazole, β-carboline,chromane, chromene, cinnoline, furan, imidazole, indazole, indole,indoline, indolizine, isobenzofuran, isochromene, isoindole,isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine,oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline,phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole,pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline,quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole,thiophene, triazole, xanthene, and the like.

“Substituted” refers to a group in which one or more hydrogen atoms areindependently replaced with the same or different substituent(s).Examples of substituents include, but are not limited to, —R⁶⁴, —R⁶⁰,—O⁻, —OH, ═O, —OR⁶⁰, —SR⁶⁰, —S⁻, ═S, —NR⁶⁰R⁶¹, ═NR⁶⁰, —CN, —CF₃, —OCN,—SCN, —NO, —NO₂, ═N₂, —N₃, —S(O)₂O⁻, —S(O)₂OH, —S(O)₂R⁶⁰, —OS(O₂)O⁻,—OS(O)₂R⁶⁰, —P(O)(O⁻)₂, —P(O)(OR⁶⁰)(O⁻), —OP(O)(OR⁶⁰)(OR⁶¹), —C(O)R⁶⁰,—C(S)R⁶⁰, —C(O)OR⁶⁰, —C(O)NR⁶⁰R⁶¹, —C(O)O⁻, —C(S)OR⁶⁰, —NR⁶²C(O)NR⁶⁰R⁶¹,—NR⁶²C(S)NR⁶⁰R⁶¹, —NR⁶²C(NR⁶³)NR⁶⁰R⁶¹, —C(NR⁶²)NR⁶⁰R⁶¹, —S(O)₂, NR⁶⁰R⁶¹,NR⁶³S(O)₂R⁶⁰, —NR⁶³C(O)R⁶⁰, and —S(O)R⁶⁰;

wherein each —R⁶⁴ is independently a halogen; each R⁶⁰ and R⁶¹ areindependently alkyl, substituted alkyl, alkoxy, substituted alkoxy,cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substitutedheterocycloalkyl, aryl, substituted aryl, heteroaryl, substitutedheteroaryl, arylalkyl, substituted arylalkyl, heteroarylalkyl, orsubstituted heteroarylalkyl, or R⁶⁰ and R⁶¹ together with the nitrogenatom to which they are bonded form a heterocycloalkyl, substitutedheterocycloalkyl, heteroaryl, or substituted heteroaryl ring, and R⁶²and R⁶³ are independently alkyl, substituted alkyl, aryl, substitutedaryl, arylalkyl, substituted arylalkyl, cycloalkyl, substitutedcycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, heteroaryl,substituted heteroaryl, heteroarylalkyl, or substituted heteroarylalkyl,or R⁶² and R⁶³ together with the atom to which they are bonded form oneor more heterocycloalkyl, substituted heterocycloalkyl, heteroaryl, orsubstituted heteroaryl rings;

wherein the “substituted” substituents, as defined above for R⁶⁰, R⁶¹,R⁶², and R⁶³, are substituted with one or more, such as one, two, orthree, groups independently selected from alkyl, -alkyl-OH,—O-haloalkyl, -alkyl-NH₂, alkoxy, cycloalkyl, cycloalkylalkyl,heterocycloalkyl, heterocycloalkylalkyl, aryl, heteroaryl, arylalkyl,heteroarylalkyl, —O⁻, —OH, ═O, —O-alkyl, —O-aryl, —O-heteroarylalkyl,—O-cycloalkyl, —O-heterocycloalkyl, —SH, —S⁻, ═S, —S-alkyl, —S-aryl,—S-heteroarylalkyl, —S-cycloalkyl, —S-heterocycloalkyl, —NH₂, ═NH, —CN,—CF₃, —OCN, —SCN, —NO, —NO₂, ═N₂, —N₃, —S(O)₂O⁻, —S(O)₂, —S(O)₂OH,—OS(O₂)O⁻, —SO₂(alkyl), —SO₂(phenyl), —SO₂(haloalkyl), —SO₂NH₂,—SO₂NH(alkyl), —SO₂NH(phenyl), —P(O)(O⁻)₂, —P(O)(O-alkyl)(O⁻),—OP(O)(O-alkyl)(O-alkyl), —CO₂H, —C(O)O(alkyl), —CON(alkyl)(alkyl),—CONH(alkyl), —CONH₂, —C(O)(alkyl), —C(O)(phenyl), —C(O)(haloalkyl),—OC(O)(alkyl), —N(alkyl)(alkyl), —NH(alkyl), —N(alkyl)(alkylphenyl),—NH(alkylphenyl), —NHC(O)(alkyl), —NHC(O)(phenyl), —N(alkyl)C(O)(alkyl),and —N(alkyl)C(O)(phenyl).

As used in this specification and the appended claims, the articles “a,”“an,” and “the” include plural referents unless expressly andunequivocally limited to one referent.

All numerical ranges herein include all numerical values and ranges ofall numerical values within the recited range of numerical values.

The present disclosure relates to estolide compounds, compositions andmethods of making the same. In certain embodiments, the presentdisclosure also relates to estolide compounds, compositions comprisingestolide compounds, for high- and low-viscosity base oil stocks andlubricants, the synthesis of such compounds, and the formulation of suchcompositions. In certain embodiments, the present disclosure relates tobiosynthetic estolides having desired viscometric properties, whileretaining or even improving other properties such as oxidative stabilityand pour point. In certain embodiments, new methods of preparingestolide compounds exhibiting such properties are provided. The presentdisclosure also relates to compositions comprising certain estolidecompounds exhibiting such properties.

In certain embodiments the composition comprises at least one estolidecompound of Formula I:

-   -   wherein    -   x is, independently for each occurrence, an integer selected        from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,        17, 18, 19, and 20;    -   y is, independently for each occurrence, an integer selected        from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,        17, 18, 19, and 20;    -   n is an integer selected from 0 to 12;    -   R₁ is an optionally substituted alkyl that is saturated or        unsaturated, and branched or unbranched; and    -   R₂ is selected from hydrogen and optionally substituted alkyl        that is saturated or unsaturated, and branched or unbranched;    -   wherein each fatty acid chain residue of said at least one        compound is independently optionally substituted.

In certain embodiments the composition comprises at least one estolidecompound of Formula II:

-   -   wherein    -   n is an integer greater than or equal to 0;    -   R₁ is an optionally substituted alkyl that is saturated or        unsaturated, and branched or unbranched;    -   R₂ is selected from hydrogen and optionally substituted alkyl        that is saturated or unsaturated, and branched or unbranched;        and    -   R₃ and R₄, independently for each occurrence, are selected from        optionally substituted alkyl that is saturated or unsaturated,        and branched or unbranched.

In certain embodiments, the composition comprises at least one estolideof Formula I, II, or III where R₁ is hydrogen.

The terms “chain” or “fatty acid chain” or “fatty acid chain residue,”as used with respect to the estolide compounds of Formula I, II, andIII, refer to one or more of the fatty acid residues incorporated inestolide compounds, e.g., R₃ or R₄ of Formula II, or the structuresrepresented by CH₃(CH₂)_(y)CH(CH₂)_(x)C(O)O— in Formula I and III.

The R₁ in Formula I, II, and III at the top of each Formula shown is anexample of what may be referred to as a “cap” or “capping material,” asit “caps” the top of the estolide. Similarly, the capping group may bean organic acid residue of general formula —OC(O)-alkyl, i.e., acarboxylic acid with a substituted or unsubstituted, saturated orunsaturated, and/or branched or unbranched alkyl as defined herein, or aformic acid residue. In certain embodiments, the “cap” or “cappinggroup” is a fatty acid. In certain embodiments, the capping group,regardless of size, is substituted or unsubstituted, saturated orunsaturated, and/or branched or unbranched. The cap or capping materialmay also be referred to as the primary or alpha (α) chain.

Depending on the manner in which the estolide is synthesized, the cap orcapping group alkyl may be the only alkyl from an organic acid residuein the resulting estolide that is unsaturated. In certain embodiments,it may be desirable to use a saturated organic or fatty-acid cap toincrease the overall saturation of the estolide and/or to increase theresulting estolide's stability. For example, in certain embodiments, itmay be desirable to provide a method of providing a saturated cappedestolide by hydrogenating an unsaturated cap using any suitable methodsavailable to those of ordinary skill in the art. Hydrogenation may beused with various sources of the fatty-acid feedstock, which may includemono- and/or polyunsaturated fatty acids. Without being bound to anyparticular theory, in certain embodiments, hydrogenating the estolidemay help to improve the overall stability of the molecule. However, afully-hydrogenated estolide, such as an estolide with a larger fattyacid cap, may exhibit increased pour point temperatures. In certainembodiments, it may be desirable to offset any loss in desirablepour-point characteristics by using shorter, saturated cappingmaterials.

The R₄C(O)O— of Formula II or structure CH₃(CH₂)_(y)CH(CH₂)_(x)C(O)O— ofFormula I and III serve as the “base” or “base chain residue” of theestolide. Depending on the manner in which the estolide is synthesized,the base organic acid or fatty acid residue may be the only residue thatremains in its free-acid form after the initial synthesis of theestolide. However, in certain embodiments, in an effort to alter orimprove the properties of the estolide, the free acid may be reactedwith any number of substituents. For example, it may be desirable toreact the free acid estolide with alcohols, glycols, amines, or othersuitable reactants to provide the corresponding ester, amide, or otherreaction products. The base or base chain residue may also be referredto as tertiary or gamma (γ) chains.

The R₃C(O)O— of Formula II or structure CH₃(CH₂)_(y)CH(CH₂)_(x)C(O)O— ofFormula I and III are linking residues that link the capping materialand the base fatty-acid residue together. There may be any number oflinking residues in the estolide, including when n=0 and the estolide isin its dimer form. Depending on the manner in which the estolide isprepared, a linking residue may be a fatty acid and may initially be inan unsaturated form during synthesis. In some embodiments, the estolidewill be formed when a catalyst is used to produce a carbocation at thefatty acid's site of unsaturation, which is followed by nucleophilicattack on the carbocation by the carboxylic group of another fatty acid.In some embodiments, it may be desirable to have a linking fatty acidthat is monounsaturated so that when the fatty acids link together, allof the sites of unsaturation are eliminated. The linking residue(s) mayalso be referred to as secondary or beta (β) chains.

In certain embodiments, the cap is an acetyl group, the linkingresidue(s) is one or more fatty acid residues, and the base chainresidue is a fatty acid residue. In certain embodiments, the linkingresidues present in an estolide differ from one another. In certainembodiments, one or more of the linking residues differs from the basechain residue.

As noted above, in certain embodiments, suitable unsaturated fatty acidsfor preparing the estolides may include any mono- or polyunsaturatedfatty acid. For example, monounsaturated fatty acids, along with asuitable catalyst, will form a single carbocation that allows for theaddition of a second fatty acid, whereby a single link between two fattyacids is formed. Suitable monounsaturated fatty acids may include, butare not limited to, palmitoleic acid (16:1), vaccenic acid (18:1), oleicacid (18:1), eicosenoic acid (20:1), erucic acid (22:1), and nervonicacid (24:1). In addition, in certain embodiments, polyunsaturated fattyacids may be used to create estolides. Suitable polyunsaturated fattyacids may include, but are not limited to, hexadecatrienoic acid (16:3),alpha-linolenic acid (18:3), stearidonic acid (18:4), eicosatrienoicacid (20:3), eicosatetraenoic acid (20:4), eicosapentaenoic acid (20:5),heneicosapentaenoic acid (21:5), docosapentaenoic acid (22:5),docosahexaenoic acid (22:6), tetracosapentaenoic acid (24:5),tetracosahexaenoic acid (24:6), linoleic acid (18:2), gamma-linoleicacid (18:3), eicosadienoic acid (20:2), dihomo-gamma-linolenic acid(20:3), arachidonic acid (20:4), docosadienoic acid (20:2), adrenic acid(22:4), docosapentaenoic acid (22:5), tetracosatetraenoic acid (22:4),tetracosapentaenoic acid (24:5), pinolenic acid (18:3), podocarpic acid(20:3), rumenic acid (18:2), alpha-calendic acid (18:3), beta-calendicacid (18:3), jacaric acid (18:3), alpha-eleostearic acid (18:3),beta-eleostearic (18:3), catalpic acid (18:3), punicic acid (18:3),rumelenic acid (18:3), alpha-parinaric acid (18:4), beta-parinaric acid(18:4), and bosseopentaenoic acid (20:5).

The process for preparing the estolide compounds described herein mayinclude the use of any natural or synthetic fatty acid source. However,it may be desirable to source the fatty acids from a renewablebiological feedstock. Suitable starting materials of biological originmay include plant fats, plant oils, plant waxes, animal fats, animaloils, animal waxes, fish fats, fish oils, fish waxes, algal oils andmixtures thereof. Other potential fatty acid sources may include wasteand recycled food-grade fats and oils, fats, oils, and waxes obtained bygenetic engineering, fossil fuel-based materials and other sources ofthe materials desired.

In some embodiments, the estolide comprises fatty-acid chains of varyinglengths. In some embodiments, x is, independently for each occurrence,an integer selected from 0 to 20, 0 to 18, 0 to 16, 0 to 14, 1 to 12, 1to 10, 2 to 8, 6 to 8, or 4 to 6. In some embodiments, x is,independently for each occurrence, an integer selected from 7 and 8. Insome embodiments, x is, independently for each occurrence, an integerselected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, and 20.

In some embodiments, y is, independently for each occurrence, an integerselected from 0 to 20, 0 to 18, 0 to 16, 0 to 14, 1 to 12, 1 to 10, 2 to8, 6 to 8, or 4 to 6. In some embodiments, y is, independently for eachoccurrence, an integer selected from 7 and 8. In some embodiments, y is,independently for each occurrence, an integer selected from 0, 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20.

In some embodiments, x+y is, independently for each chain, an integerselected from 0 to 40, 0 to 20, 10 to 20, or 12 to 18. In someembodiments, x+y is, independently for each chain, an integer selectedfrom 13 to 15. In some embodiments, x+y is 15. In some embodiments, x+yis, independently for each chain, an integer selected from 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24.

In some embodiments, the estolide compound of Formula I, II, or DI maycomprise any number of fatty acid residues to form an “n-mer” estolide.For example, the estolide may be in its dimer (n=0), trimer (n=1),tetramer (n=2), pentamer (n=3), hexamer (n=4), heptamer (n=5), octamer(n=6), nonamer (n=7), or decamer (n=8) form. In some embodiments, n isan integer selected from 0 to 20, 0 to 18, 0 to 16, 0 to 14, 0 to 12, 0to 10, 0 to 8, or 0 to 6. In some embodiments, n is an integer selectedfrom 0 to 4. In some embodiments, n is 1, wherein said at least onecompound of Formula I, II, or III comprises the trimer. In someembodiments, n is greater than 1. In some embodiments, n is an integerselected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, and 20.

In some embodiments, R₁ of Formula I, II, or III is an optionallysubstituted alkyl that is saturated or unsaturated, and branched orunbranched. In some embodiments, the alkyl group is a C₁ to C₄₀ alkyl,C₁ to C₂₂ alkyl or C₁ to C₁₈ alkyl. In some embodiments, the alkyl groupis selected from C₇ to C₁₇ alkyl. In some embodiments, R₁ is selectedfrom C₇ alkyl, C₉ alkyl, C₁₁ alkyl, C₁₃ alkyl, C₁₅ alkyl, and C₁₇ alkyl.In some embodiments, R₁ is selected from C₁₃ to C₁₇ alkyl, such as fromC₁₃ alkyl, C₁₅ alkyl, and C₁₇ alkyl. In some embodiments, R₁ is a C₁,C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇,C₁₈, C₁₉, C₂₀, C₂₁, or C₂₂ alkyl.

In some embodiments, R₂ of Formula I, II, or III is an optionallysubstituted alkyl that is saturated or unsaturated, and branched orunbranched. In some embodiments, the alkyl group is a C₁ to C₄₀ alkyl,C₁ to C₂₂ alkyl or C₁ to C₁₈ alkyl. In some embodiments, the alkyl groupis selected from C₇ to C₁₇ alkyl. In some embodiments, R₂ is selectedfrom C₇ alkyl, C₉ alkyl, C₁₁ alkyl, C₁₃ alkyl, C₁₅ alkyl, and C₁₇ alkyl.In some embodiments, R₂ is selected from C₁₃ to C₁₇ alkyl, such as fromC₁₃ alkyl, C₁₅ alkyl, and C₁₇ alkyl. In some embodiments, R₂ is a C₁,C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇,C₁₈, C₁₉, C₂₀, C₂₁, or C₂₂ alkyl.

In some embodiments, R₃ is an optionally substituted alkyl that issaturated or unsaturated, and branched or unbranched. In someembodiments, the alkyl group is a C₁ to C₄₀ alkyl, C₁ to C₂₂ alkyl or C₁to C₁₈ alkyl. In some embodiments, the alkyl group is selected from C₇to C₁₇ alkyl. In some embodiments, R₃ is selected from C₇ alkyl, C₉alkyl, C₁₁ alkyl, C₁₃ alkyl, C₁₅ alkyl, and C₁₇ alkyl. In someembodiments, R₃ is selected from C₁₃ to C₁₇ alkyl, such as from C₁₃alkyl, C₁₅ alkyl, and C₁₇ alkyl. In some embodiments, R₃ is a C₁, C₂,C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇, C₁₈,C₁₉, C₂₀, C₂₁, or C₂₂ alkyl.

In some embodiments, R₄ is an optionally substituted alkyl that issaturated or unsaturated, and branched or unbranched. In someembodiments, the alkyl group is a C₁ to C₄₀ alkyl, C₁ to C₂₂ alkyl or C₁to C₁₈ alkyl. In some embodiments, the alkyl group is selected from C₇to C₁₇ alkyl. In some embodiments, R₄ is selected from C₇ alkyl, C₉alkyl, C₁₁ alkyl, C₁₃ alkyl, C₁₅ alkyl, and C₁₇ alkyl. In someembodiments, R₄ is selected from C₁₃ to C₁₇ alkyl, such as from C₁₃alkyl, C₁₅ alkyl, and C₁₇ alkyl. In some embodiments, R₄ is a C₁, C₂,C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇, C₁₈,C₁₉, C₂₀, C₂₁, or C₂₂ alkyl.

As noted above, in certain embodiments, it may be possible to manipulateone or more of the estolides' properties by altering the length of R₁and/or its degree of saturation. However, in certain embodiments, thelevel of substitution on R₁ may also be altered to change or evenimprove the estolides' properties. Without being bound to any particulartheory, in certain embodiments, it is believed that the presence ofpolar substituents on R₁, such as one or more hydroxy groups, mayincrease the viscosity of the estolide, while increasing pour point.Accordingly, in some embodiments, R₁ will be unsubstituted or optionallysubstituted with a group that is not hydroxyl.

In some embodiments, the estolide is in its free-acid form, wherein R₂of Formula I, II, or III is hydrogen. In some embodiments, R₂ isselected from optionally substituted alkyl that is saturated orunsaturated, and branched or unbranched. In certain embodiments, the R₂residue may comprise any desired alkyl group, such as those derived fromesterification of the estolide with the alcohols identified in theexamples herein. In some embodiments, the alkyl group is selected fromC₁ to C₄₀, C₁ to C₂₂, C₃ to C₂₀, C₁ to C₁₈, or C₆ to C₁₂ alkyl. In someembodiments, R₂ may be selected from C₃ alkyl, C₄ alkyl, C₈ alkyl, C₁₂alkyl, C₁₆ alkyl, C₁₈ alkyl, and C₂₀ alkyl. For example, in certainembodiments, R₂ may be branched, such as isopropyl, isobutyl, or2-ethylhexyl. In some embodiments, R₂ may be a larger alkyl group,branched or unbranched, comprising C₁₂ alkyl, C₁₆ alkyl, C₁₈ alkyl, orC₂₀ alkyl. Such groups at the R₂ position may be derived fromesterification of the free-acid estolide using the Jarcol™ line ofalcohols marketed by Jarchem Industries, Inc. of Newark, N.J., includingJarcol™ I-18CG, I-20, I-12, I-16, I-18T, and 85BJ. In some cases, R₂ maybe sourced from certain alcohols to provide branched alkyls such asisostearyl and isopalmityl. It should be understood that suchisopalmityl and isostearyl alkyl groups may cover any branched variationof C₁₆ and C₁₈, respectively. For example, the estolides describedherein may comprise highly-branched isopalmityl or isostearyl groups atthe R₂ position, derived from the Fineoxocol® line of isopalmityl andisostearyl alcohols marketed by Nissan Chemical America Corporation ofHouston, Tex., including Fineoxocol® 180, 180N, and 1600. Without beingbound to any particular theory, in embodiments, large, highly-branchedalkyl groups (e.g., isopalmityl and isostearyl) at the R₂ position ofthe estolides can provide at least one way to increase the lubricant'sviscosity, while substantially retaining or even reducing its pourpoint.

In some embodiments, the compounds described herein may comprise amixture of two or more estolide compounds of Formula I, II, and III. Itis possible to characterize the chemical makeup of an estolide, amixture of estolides, or a composition comprising estolides, by usingthe compound's, mixture's, or composition's measured estolide number(EN) of compound or composition. The EN represents the average number offatty acids added to the base fatty acid. The EN also represents theaverage number of estolide linkages per molecule:EN=n+1wherein n is the number of secondary (β) fatty acids. Accordingly, asingle estolide compound will have an EN that is a whole number, forexample for dimers, trimers, and tetramers:dimer EN=1trimer EN=2tetramer EN=3

However, a composition comprising two or more estolide compounds mayhave an EN that is a whole number or a fraction of a whole number. Forexample, a composition having a 1:1 molar ratio of dimer and trimerwould have an EN of 1.5, while a composition having a 1:1 molar ratio oftetramer and trimer would have an EN of 2.5.

In some embodiments, the compositions may comprise a mixture of two ormore estolides having an EN that is an integer or fraction of an integerthat is greater than 4.5, or even 5.0. In some embodiments, the EN maybe an integer or fraction of an integer selected from about 1.0 to about5.0. In some embodiments, the EN is an integer or fraction of an integerselected from 1.2 to about 4.5. In some embodiments, the EN is selectedfrom a value greater than 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6,2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, 5.2, 5.4,5.6 and 5.8. In some embodiments, the EN is selected from a value lessthan 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6,3.8, 4.0, 4.2, 4.4, 4.6, 4.8, and 5.0, 5.2, 5.4, 5.6, 5.8, and 6.0. Insome embodiments, the EN is selected from 1, 1.2, 1.4, 1.6, 1.8, 2.0,2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8,5.0, 5.2, 5.4, 5.6, 5.8, and 6.0.

As noted above, it should be understood that the chains of the estolidecompounds may be independently optionally substituted, wherein one ormore hydrogens are removed and replaced with one or more of thesubstituents identified herein. Similarly, two or more of the hydrogenresidues may be removed to provide one or more sites of unsaturation,such as a cis or trans double bond. Further, the chains may optionallycomprise branched hydrocarbon residues. For example, in some embodimentsthe estolides described herein may comprise at least one compound ofFormula II:

-   -   wherein    -   n is an integer equal to or greater than 0;    -   R₁ is an optionally substituted alkyl that is saturated or        unsaturated, and branched or unbranched    -   R₂ is selected from hydrogen and optionally substituted alkyl        that is saturated or unsaturated, and branched or unbranched;        and    -   R₃ and R₄, independently for each occurrence, are selected from        optionally substituted alkyl that is saturated or unsaturated,        and branched or unbranched.

In some embodiments, n is an integer selected from 1 to 20. In someembodiments, n is an integer selected from 1 to 12. In some embodiments,n is an integer selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, 16, 17, 18, 19 and 20. In some embodiments, one or more R₃differs from one or more other R₃ in a compound of Formula II. In someembodiments, one or more R₃ differs from R₄ in a compound of Formula II.In some embodiments, if the compounds of Formula II are prepared fromone or more polyunsaturated fatty acids, it is possible that one or moreof R₃ and R₄ will have one or more sites of unsaturation. In someembodiments, if the compounds of Formula II are prepared from one ormore branched fatty acids, it is possible that one or more of R₃ and R₄will be branched.

In some embodiments, R₃ and R₄ can be CH₃(CH₂)_(y)CH(CH₂)_(x)—, where xis, independently for each occurrence, an integer selected from 0, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20, andy is, independently for each occurrence, an integer selected from 0, 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20.Where both R₃ and R₄ are CH₃(CH₂)_(y)CH(CH₂)_(x)—, the compounds may becompounds according to Formula I and III.

Without being bound to any particular theory, in certain embodiments,altering the EN produces estolides having desired viscometric propertieswhile substantially retaining or even reducing pour point. For example,in some embodiments the estolides exhibit a decreased pour point uponincreasing the EN value. Accordingly, in certain embodiments, a methodis provided for retaining or decreasing the pour point of an estolidebase oil by increasing the EN of the base oil, or a method is providedfor retaining or decreasing the pour point of a composition comprisingan estolide base oil by increasing the EN of the base oil. In someembodiments, the method comprises: selecting an estolide base oil havingan initial EN and an initial pour point; and removing at least a portionof the base oil, said portion exhibiting an EN that is less than theinitial EN of the base oil, wherein the resulting estolide base oilexhibits an EN that is greater than the initial EN of the base oil, anda pour point that is equal to or lower than the initial pour point ofthe base oil. In some embodiments, the selected estolide base oil isprepared by oligomerizing at least one first unsaturated fatty acid withat least one second unsaturated fatty acid and/or saturated fatty acid.In some embodiments, the removing at least a portion of the base oil isaccomplished by distillation, chromatography, membrane separation, phaseseparation, affinity separation, solvent extraction, or combinationsthereof. In some embodiments, the distillation takes place at atemperature and/or pressure that is suitable to separate the estolidebase oil into different “cuts” that individually exhibit different ENvalues. In some embodiments, this may be accomplished by subjecting thebase oil temperature of at least about 250° C. and an absolute pressureof no greater than about 25 microns. In some embodiments, thedistillation takes place at a temperature range of about 250° C. toabout 310° C. and an absolute pressure range of about 10 microns toabout 25 microns.

In some embodiments, estolide compounds and compositions exhibit an ENthat is greater than or equal to 1, such as an integer or fraction of aninteger selected from about 1.0 to about 2.0. In some embodiments, theEN is an integer or fraction of an integer selected from about 1.0 toabout 1.6. In some embodiments, the EN is a fraction of an integerselected from about 1.1 to about 1.5. In some embodiments, the EN isselected from a value greater than 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6,1.7, 1.8, and 1.9. In some embodiments, the EN is selected from a valueless than 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0.

In some embodiments, the EN is greater than or equal to 1.5, such as aninteger or fraction of an integer selected from about 1.8 to about 2.8.In some embodiments, the EN is an integer or fraction of an integerselected from about 2.0 to about 2.6. In some embodiments, the EN is afraction of an integer selected from about 2.1 to about 2.5. In someembodiments, the EN is selected from a value greater than 1.8, 1.9, 2.0,2.1, 2.2, 2.3, 2.4, 2.5, 2.6, and 2.7. In some embodiments, the EN isselected from a value less than 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6,2.7, and 2.8. In some embodiments, the EN is about 1.8, 2.0, 2.2, 2.4,2.6, or 2.8.

In some embodiments, the EN is greater than or equal to about 4, such asan integer or fraction of an integer selected from about 4.0 to about5.0. In some embodiments, the EN is a fraction of an integer selectedfrom about 4.2 to about 4.8. In some embodiments, the EN is a fractionof an integer selected from about 4.3 to about 4.7. In some embodiments,the EN is selected from a value greater than 4.0, 4.1, 4.2, 4.3, 4.4,4.5, 4.6, 4.7, 4.8, and 4.9. In some embodiments, the EN is selectedfrom a value less than 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, and5.0. In some embodiments, the EN is about 4.0, 4.2, 4.4, 4.6, 4.8, or5.0.

In some embodiments, the EN is greater than or equal to about 5, such asan integer or fraction of an integer selected from about 5.0 to about6.0. In some embodiments, the EN is a fraction of an integer selectedfrom about 5.2 to about 5.8. In some embodiments, the EN is a fractionof an integer selected from about 5.3 to about 5.7. In some embodiments,the EN is selected from a value greater than 5.0, 5.1, 5.2, 5.3, 5.4,5.5, 5.6, 5.7, 5.8, and 5.9. In some embodiments, the EN is selectedfrom a value less than 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, and6.0. In some embodiments, the EN is about 5.0, 5.2, 5.4, 5.4, 5.6, 5.8,or 6.0.

In some embodiments, the EN is greater than or equal to 1, such as aninteger or fraction of an integer selected from about 1.0 to about 2.0.In some embodiments, the EN is a fraction of an integer selected fromabout 1.1 to about 1.7. In some embodiments, the EN is a fraction of aninteger selected from about 1.1 to about 1.5. In some embodiments, theEN is selected from a value greater than 1.0, 1.1, 1.2, 1.3, 1.4, 1.5,1.6, 1.7, 1.8, or 1.9. In some embodiments, the EN is selected from avalue less than 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0. In someembodiments, the EN is about 1.0, 1.2, 1.4, 1.6, 1.8, or 2.0. In someembodiments, the EN is greater than or equal to 1, such as an integer orfraction of an integer selected from about 1.2 to about 2.2. In someembodiments, the EN is an integer or fraction of an integer selectedfrom about 1.4 to about 2.0. In some embodiments, the EN is a fractionof an integer selected from about 1.5 to about 1.9. In some embodiments,the EN is selected from a value greater than 1.0, 1.1. 1.2, 1.3, 1.4,1.5, 1.6, 1.7, 1.8, 1.9, 2.0, and 2.1. In some embodiments, the EN isselected from a value less than 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9,2.0, 2.1, and 2.2. In some embodiments, the EN is about 1.0, 1.2, 1.4,1.6, 1.8, 2.0, or 2.2.

In some embodiments, the EN is greater than or equal to 2, such as aninteger or fraction of an integer selected from about 2.8 to about 3.8.In some embodiments, the EN is an integer or fraction of an integerselected from about 2.9 to about 3.5. In some embodiments, the EN is aninteger or fraction of an integer selected from about 3.0 to about 3.4.In some embodiments, the EN is selected from a value greater than 2.0,2.1, 2.2, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.4, 3.5, 3.6, and3.7. In some embodiments, the EN is selected from a value less than 2.2,2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6,3.7, and 3.8. In some embodiments, the EN is about 2.0, 2.2, 2.4, 2.6,2.8, 3.0, 3.2, 3.4, 3.6, or 3.8. Typically, base stocks and lubricantcompositions exhibit certain lubricity, viscosity, and/or pour pointcharacteristics. For example, in certain embodiments, suitable viscositycharacteristics of the base oil may range from about 10 cSt to about 250cSt at 40° C., and/or about 3 cSt to about 30 cSt at 100° C. In someembodiments, the compounds and compositions may exhibit viscositieswithin a range from about 50 cSt to about 150 cSt at 40° C., and/orabout 10 cSt to about 20 cSt at 100° C.

In some embodiments, the estolide compounds and compositions may exhibitviscosities less than about 55 cSt at 40° C. or less than about 45 cStat 40° C., and/or less than about 12 cSt at 100° C. or less than about10 cSt at 100° C. In some embodiments, the estolide compounds andcompositions may exhibit viscosities within a range from about 25 cSt toabout 55 cSt at 40° C., and/or about 5 cSt to about 11 cSt at 100° C. Insome embodiments, the estolide compounds and compositions may exhibitviscosities within a range from about 35 cSt to about 45 cSt at 40° C.,and/or about 6 cSt to about 10 cSt at 100° C. In some embodiments, theestolide compounds and compositions may exhibit viscosities within arange from about 38 cSt to about 43 cSt at 40° C., and/or about 7 cSt toabout 9 cSt at 100° C.

In some embodiments, the estolide compounds and compositions may exhibitviscosities less than about 120 cSt at 40° C. or less than about 100 cStat 40° C., and/or less than about 18 cSt at 100° C. or less than about17 cSt at 100° C. In some embodiments, the estolide compounds andcompositions may exhibit a viscosity within a range from about 70 cSt toabout 120 cSt at 40° C., and/or about 12 cSt to about 18 cSt at 100° C.In some embodiments, the estolide compounds and compositions may exhibitviscosities within a range from about 80 cSt to about 100 cSt at 40° C.,and/or about 13 cSt to about 17 cSt at 100° C. In some embodiments, theestolide compounds and compositions may exhibit viscosities within arange from about 85 cSt to about 95 cSt at 40° C., and/or about 14 cStto about 16 cSt at 100° C.

In some embodiments, the estolide compounds and compositions may exhibitviscosities greater than about 180 cSt at 40° C. or greater than about200 cSt at 40° C., and/or greater than about 20 cSt at 100° C. orgreater than about 25 cSt at 100° C. In some embodiments, the estolidecompounds and compositions may exhibit a viscosity within a range fromabout 180 cSt to about 230 cSt at 40° C., and/or about 25 cSt to about31 cSt at 100° C. In some embodiments, estolide compounds andcompositions may exhibit viscosities within a range from about 200 cStto about 250 cSt at 40° C., and/or about 25 cSt to about 35 cSt at 100°C. In some embodiments, estolide compounds and compositions may exhibitviscosities within a range from about 210 cSt to about 230 cSt at 40°C., and/or about 28 cSt to about 33 cSt at 100° C. In some embodiments,the estolide compounds and compositions may exhibit viscosities within arange from about 200 cSt to about 220 cSt at 40° C., and/or about 26 cStto about 30 cSt at 100° C. In some embodiments, the estolide compoundsand compositions may exhibit viscosities within a range from about 205cSt to about 215 cSt at 40° C., and/or about 27 cSt to about 29 cSt at100° C.

In some embodiments, the estolide compounds and compositions may exhibitviscosities less than about 45 cSt at 40° C. or less than about 38 cStat 40° C., and/or less than about 10 cSt at 100° C. or less than about 9cSt at 100° C. In some embodiments, the estolide compounds andcompositions may exhibit a viscosity within a range from about 20 cSt toabout 45 cSt at 40° C., and/or about 4 cSt to about 10 cSt at 100° C. Insome embodiments, the estolide compounds and compositions may exhibitviscosities within a range from about 28 cSt to about 38 cSt at 40° C.,and/or about 5 cSt to about 9 cSt at 100° C. In some embodiments, theestolide compounds and compositions may exhibit viscosities within arange from about 30 cSt to about 35 cSt at 40° C., and/or about 6 cSt toabout 8 cSt at 100° C.

In some embodiments, the estolide compounds and compositions may exhibitviscosities less than about 80 cSt at 40° C. or less than about 70 cStat 40° C., and/or less than about 14 cSt at 100° C. or less than about13 cSt at 100° C. In some embodiments, the estolide compounds andcompositions may exhibit a viscosity within a range from about 50 cSt toabout 80 cSt at 40° C., and/or about 8 cSt to about 14 cSt at 100° C. Insome embodiments, the estolide compounds and compositions may exhibitviscosities within a range from about 60 cSt to about 70 cSt at 40° C.,and/or about 9 cSt to about 13 cSt at 100° C. In some embodiments, theestolide compounds and compositions may exhibit viscosities within arange from about 63 cSt to about 68 cSt at 40° C., and/or about 10 cStto about 12 cSt at 100° C.

In some embodiments, the estolide compounds and compositions may exhibitviscosities greater than about 120 cSt at 40° C. or greater than about130 cSt at 40° C., and/or greater than about 15 cSt at 100° C. orgreater than about 18 cSt at 100° C. In some embodiments, the estolidecompounds and compositions may exhibit a viscosity within a range fromabout 120 cSt to about 150 cSt at 40° C., and/or about 16 cSt to about24 cSt at 100° C. In some embodiments, the estolide compounds andcompositions may exhibit viscosities within a range from about 130 cStto about 160 cSt at 40° C., and/or about 17 cSt to about 28 cSt at 100°C. In some embodiments, the estolide compounds and compositions mayexhibit viscosities within a range from about 130 cSt to about 145 cStat 40° C., and/or about 17 cSt to about 23 cSt at 100° C. In someembodiments, the estolide compounds and compositions may exhibitviscosities within a range from about 135 cSt to about 140 cSt at 40°C., and/or about 19 cSt to about 21 cSt at 100° C. In some embodiments,the estolide compounds and compositions may exhibit viscosities of about1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 34, 36, 38, 40, 42, 44, 46,48, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140,150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280,290, 300, 350, or 400 cSt. at 40° C. In some embodiments, the estolidecompounds and compositions may exhibit viscosities of about 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, and 30 cSt at 100° C. In certain embodiments,estolides may exhibit desirable low-temperature pour point properties.In some embodiments, the estolide compounds and compositions may exhibita pour point lower than about −25° C., about −35° C., −40° C., or evenabout −50° C. In some embodiments, the estolide compounds andcompositions have a pour point of about −25° C. to about −45° C. In someembodiments, the pour point falls within a range of about −30° C. toabout −40° C., about −34° C. to about −38° C., about −30° C. to about−45° C., −35° C. to about −45° C., 34° C. to about −42° C., about −38°C. to about −42° C., or about 36° C. to about −40° C. In someembodiments, the pour point falls within the range of about −27° C. toabout −37° C., or about −30° C. to about −34° C. In some embodiments,the pour point falls within the range of about −25° C. to about −35° C.,or about −28° C. to about −32° C. In some embodiments, the pour pointfalls within the range of about −28° C. to about −38° C., or about −31°C. to about −35° C. In some embodiments, the pour point falls within therange of about −31° C. to about −41° C., or about −34° C. to about −38°C. In some embodiments, the pour point falls within the range of about−40° C. to about −50° C., or about −42° C. to about −48° C. In someembodiments, the pour point falls within the range of about −50° C. toabout −60° C., or about −52° C. to about −58° C. In some embodiments,the upper bound of the pour point is less than about −35° C., about −36°C., about −37° C., about −38° C., about −39° C., about −40° C., about−41° C., about −42° C., about −43° C., about −44° C., or about −45° C.In some embodiments, the lower bound of the pour point is greater thanabout −70° C., about −69° C., about −68° C., about −67° C., about −66°C., about −65° C., about −64° C., about −63° C., about −62° C., about−61° C., about −60° C., about −59° C., about −58° C., about −57° C.,about −56° C., −55° C., about −54° C., about −53° C., about −52° C.,−51, about −50° C., about −49° C., about −48° C., about −47° C., about−46° C., or about −45° C.

In addition, in certain embodiments, the estolides may exhibit decreasedIodine Values (IV) when compared to estolides prepared by other methods.IV is a measure of the degree of total unsaturation of an oil, and isdetermined by measuring the amount of iodine per gram of estolide(cg/g). In certain instances, oils having a higher degree ofunsaturation may be more susceptible to creating corrosiveness anddeposits, and may exhibit lower levels of oxidative stability. Compoundshaving a higher degree of unsaturation will have more points ofunsaturation for iodine to react with, resulting in a higher IV. Thus,in certain embodiments, it may be desirable to reduce the IV ofestolides in an effort to increase the oil's oxidative stability, whilealso decreasing harmful deposits and the corrosiveness of the oil.

In some embodiments, estolide compounds and compositions describedherein have an N of less than about 40 cg/g or less than about 35 cg/g.In some embodiments, estolides have an IV of less than about 30 cg/g,less than about 25 cg/g, less than about 20 cg/g, less than about 15cg/g, less than about 10 cg/g, or less than about 5 cg/g. The IV of acomposition may be reduced by decreasing the estolide's degree ofunsaturation. This may be accomplished by, for example, by increasingthe amount of saturated capping materials relative to unsaturatedcapping materials when synthesizing the estolides. Alternatively, incertain embodiments, IV may be reduced by hydrogenating estolides havingunsaturated caps.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 1; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 2; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 3; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 4; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 5; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 6; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 7; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₇ alkyl; n is 8; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 1; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 2; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 3; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 4; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 5; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 6; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 7; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₂₁ alkyl; n is 8; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 1; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 2; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 3; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 4; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 5; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 6; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 7; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₅ alkyl; n is 8; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 1; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 2; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 3; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 4; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 5; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 6; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 7; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

In some embodiments, estolides comprise at least one compound of FormulaII, wherein: one or more of R₁, R₃ and R₄ are selected from a saturatedand unbranched C₁₉ alkyl; n is 8; and R₂ is an optionally substitutedC₁-C₄₀ alkyl that is saturated or unsaturated and branched orunbranched.

The present disclosure further relates to methods of making estolidesaccording to Formula I, II, and III. By way of example, the reaction ofan unsaturated fatty acid with an organic acid and the esterification ofthe resulting free acid estolide are illustrated and discussed in thefollowing Schemes 1 and 2. The particular structural formulas used toillustrate the reactions correspond to those for synthesis of compoundsaccording to Formula I and III; however, the methods apply equally tothe synthesis of compounds according to Formula II, with use ofcompounds having structure corresponding to R₃ and R₄ with a reactivesite of unsaturation.

As illustrated below, compound 100 represents an unsaturated fatty acidthat may serve as the basis for preparing the estolide compoundsdescribed herein.

In Scheme 1, wherein x is, independently for each occurrence, an integerselected from 0 to 20, y is, independently for each occurrence, aninteger selected from 0 to 20, n is an integer greater than or equal to1, and R₁ is an optionally substituted alkyl that is saturated orunsaturated, and branched or unbranched, unsaturated fatty acid 100 maybe combined with compound 102 and a proton from a proton source to formfree acid estolide 104. In certain embodiments, compound 102 is notincluded, and unsaturated fatty acid 100 may be exposed alone to acidicconditions to form free acid estolide 104, wherein R₁ would represent anunsaturated alkyl group. In certain embodiments, if compound 102 isincluded in the reaction, R₁ may represent one or more optionallysubstituted alkyl residues that are saturated or unsaturated andbranched or unbranched. Any suitable proton source may be implemented tocatalyze the formation of free acid estolide 104, including but notlimited to homogenous acids and/or strong acids like hydrochloric acid,sulfuric acid, perchloric acid, nitric acid, triflic acid, and the like.

Similarly, in Scheme 2, wherein x is, independently for each occurrence,an integer selected from 0 to 20, y is, independently for eachoccurrence, an integer selected from 0 to 20, n is an integer greaterthan or equal to 1, and R₁ and R2 are each an optionally substitutedalkyl that is saturated or unsaturated, and branched or unbranched, freeacid estolide 104 may be esterified by any suitable procedure known tothose of skilled in the art, such as acid-catalyzed reduction withalcohol 202, to yield esterified estolide 204. Other exemplary methodsmay include other types of Fischer esterification, such as those usingLewis acid catalysts such as BF₃.

As discussed above, in certain embodiments, the estolides describedherein may have improved properties which render them useful as basestocks for biodegradable lubricant applications. Such applications mayinclude, without limitation, crankcase oils, gearbox oils, hydraulicfluids, drilling fluids, two-cycle engine oils, greases, and the like.Other suitable uses may include marine applications, wherebiodegradability and toxicity are of concern. In certain embodiments,the nontoxic nature of certain estolides described herein may also makethem suitable for use as lubricants in the cosmetic and food industries.

In certain embodiments, the estolide compounds may meet or exceed one ormore of the specifications for certain end-use applications, without theneed for conventional additives. For example, in certain instances,high-viscosity lubricants, such as those exhibiting a kinematicviscosity of greater than about 120 cSt at 40° C., or even greater thanabout 200 cSt at 40° C., may be desired for particular applications suchas gearbox or wind turbine lubricants. Prior-known lubricants with suchproperties typically also demonstrate an increase in pour point asviscosity increases, such that prior lubricants may not be suitable forsuch applications in colder environments. However, in certainembodiments, the counterintuitive properties of certain compoundsdescribed herein (e.g., increased EN provides estolides with higherviscosities while retaining, or even decreasing, the oil's pour point)may make higher-viscosity estolides particularly suitable for suchspecialized applications.

Similarly, the use of prior-known lubricants in colder environments maygenerally result in an unwanted increase in a lubricant's viscosity.Thus, depending on the application, it may be desirable to uselower-viscosity oils at lower temperatures. In certain circumstances,low-viscosity oils may include those exhibiting a viscosity of lowerthan about 50 cSt at 40° C., or even about 40 cSt at 40° C. Accordingly,in certain embodiments, the low-viscosity estolides described herein mayprovide end users with a suitable alternative to high-viscositylubricants for operation at lower temperatures.

In some embodiments, it may be desirable to prepare lubricantcompositions comprising an estolide base stock. For example, in certainembodiments, the estolides described herein may be blended with one ormore additives selected from polyalphaolefins, synthetic esters,polyalkylene glycols, mineral oils (Groups I, II, and III), pour pointdepressants, viscosity modifiers, anti-corrosives, antiwear agents,detergents, dispersants, colorants, antifoaming agents, anddemulsifiers. In addition, or in the alternative, in certainembodiments, the estolides described herein may be co-blended with oneor more synthetic or petroleum-based oils to achieve desired viscosityand/or pour point profiles. In certain embodiments, certain estolidesdescribed herein also mix well with gasoline, so that they may be usefulas fuel components or additives.

In all of the foregoing examples, the compounds described may be usefulalone, as mixtures, or in combination with other compounds,compositions, and/or materials.

Methods for obtaining the novel compounds described herein will beapparent to those of ordinary skill in the art, suitable proceduresbeing described, for example, in the examples below, and in thereferences cited herein.

EXAMPLES

Analytics

Nuclear Magnetic Resonance: NMR spectra were collected using a BrukerAvance 500 spectrometer with an absolute frequency of 500.113 MHz at 300K using CDCl₃ as the solvent. Chemical shifts were reported as parts permillion from tetramethylsilane. The formation of a secondary ester linkbetween fatty acids, indicating the formation of estolide, was verifiedwith ¹H NMR by a peak at about 4.84 ppm.

Estolide Number (EN): The EN was measured by GC analysis. It should beunderstood that the EN of a composition specifically refers to ENcharacteristics of any estolide compounds present in the composition.Accordingly, an estolide composition having a particular EN may alsocomprise other components, such as natural or synthetic additives, othernon-estolide base oils, fatty acid esters, e.g., triglycerides, and/orfatty acids, but the EN as used herein, unless otherwise indicated,refers to the value for the estolide fraction of the estolidecomposition.

Iodine Value (IV): The iodine value is a measure of the degree of totalunsaturation of an oil. IV is expressed in terms of centigrams of iodineabsorbed per gram of oil sample. Therefore, the higher the iodine valueof an oil the higher the level of unsaturation is of that oil. The IVmay be measured and/or estimated by GC analysis. Where a compositionincludes unsaturated compounds other than estolides as set forth inFormula I, II, and III, the estolides can be separated from otherunsaturated compounds present in the composition prior to measuring theiodine value of the constituent estolides. For example, if a compositionincludes unsaturated fatty acids or triglycerides comprising unsaturatedfatty acids, these can be separated from the estolides present in thecomposition prior to measuring the iodine value for the one or moreestolides.

Acid Value: The acid value is a measure of the total acid present in anoil. Acid value may be determined by any suitable titration method knownto those of ordinary skill in the art. For example, acid values may bedetermined by the amount of KOH that is required to neutralize a givensample of oil, and thus may be expressed in terms of mg KOH/g of oil.

Gas Chromatography (GC): GC analysis was performed to evaluate theestolide number (EN) and iodine value (IV) of the estolides. Thisanalysis was performed using an Agilent 6890N series gas chromatographequipped with a flame-ionization detector and an autosampler/injectoralong with an SP-2380 30 m×0.25 mm i.d. column.

The parameters of the analysis were as follows: column flow at 1.0mL/min with a helium head pressure of 14.99 psi; split ratio of 50:1;programmed ramp of 120-135° C. at 20° C./min, 135-265° C. at 7° C./min,hold for 5 min at 265° C.; injector and detector temperatures set at250° C.

Measuring EN and IV by GC: To perform these analyses, the fatty acidcomponents of an estolide sample were reacted with MeOH to form fattyacid methyl esters by a method that left behind a hydroxy group at siteswhere estolide links were once present. Standards of fatty acid methylesters were first analyzed to establish elution times.

Sample Preparation: To prepare the samples, 10 mg of estolide wascombined with 0.5 mL of 0.5M KOH/MeOH in a vial and heated at 100° C.for 1 hour. This was followed by the addition of 1.5 mL of 1.0 MH₂SO₄/MeOH and heated at 100° C. for 15 minutes and then allowed to coolto room temperature. One (1) mL of H₂O and 1 mL of hexane were thenadded to the vial and the resulting liquid phases were mixed thoroughly.The layers were then allowed to phase separate for 1 minute. The bottomH₂O layer was removed and discarded. A small amount of drying agent(Na₂SO₄ anhydrous) was then added to the organic layer after which theorganic layer was then transferred to a 2 mL crimp cap vial andanalyzed.

EN Calculation: The EN is measured as the percent hydroxy fatty acidsdivided by the percent non-hydroxy fatty acids. As an example, a dimerestolide would result in half of the fatty acids containing a hydroxyfunctional group, with the other half lacking a hydroxyl functionalgroup. Therefore, the EN would be 50% hydroxy fatty acids divided by 50%non-hydroxy fatty acids, resulting in an EN value of 1 that correspondsto the single estolide link between the capping fatty acid and basefatty acid of the dimer.

IV Calculation: The iodine value is estimated by the following equationbased on ASTM Method D97 (ASTM International, Conshohocken, Pa.):

${IV} = {\sum{100 \times \frac{A_{f} \times M\; W_{I} \times {db}}{M\; W_{f}}}}$

-   -   A_(f)=fraction of fatty compound in the sample    -   MW₁=253.81, atomic weight of two iodine atoms added to a double        bond    -   db=number of double bonds on the fatty compound    -   MW_(f)=molecular weight of the fatty compound

The properties of exemplary estolide compounds and compositionsdescribed herein are identified in the following examples and tables.

Other Measurements: Except as otherwise described, pour point ismeasured by ASTM Method D97-96a, cloud point is measured by ASTM MethodD2500, viscosity/kinematic viscosity is measured by ASTM Method D445-97,viscosity index is measured by ASTM Method D2270-93 (Reapproved 1998),specific gravity is measured by ASTM Method D4052, flash point ismeasured by ASTM Method D92, evaporative loss is measured by ASTM MethodD5800, vapor pressure is measured by ASTM Method D5191, and acuteaqueous toxicity is measured by Organization of Economic Cooperation andDevelopment (OECD) 203.

Example 1

The acid catalyst reaction was conducted in a 50 gallon PfaudlerRT-Series glass-lined reactor. Oleic acid (65 Kg, OL 700, Twin Rivers)was added to the reactor with 70% perchloric acid (992.3 mL, AldrichCat#244252) and heated to 60° C. in vacuo (10 torr abs) for 24 hrs whilecontinuously being agitated. After 24 hours the vacuum was released.2-Ethylhexanol (29.97 Kg) was then added to the reactor and the vacuumwas restored. The reaction was allowed to continue under the sameconditions (60° C., 10 torr abs) for 4 more hours. At which time, KOH(645.58 g) was dissolved in 90% ethanol/water (5000 mL, 90% EtOH byvolume) and added to the reactor to quench the acid. The solution wasthen allowed to cool for approximately 30 minutes. The contents of thereactor were then pumped through a 1 micron (μ) filter into anaccumulator to filter out the salts. Water was then added to theaccumulator to wash the oil. The two liquid phases were thoroughly mixedtogether for approximately 1 hour. The solution was then allowed tophase separate for approximately 30 minutes. The water layer was drainedand disposed of. The organic layer was again pumped through a 1 μfilterback into the reactor. The reactor was heated to 60° C. in vacuo (10torr abs) until all ethanol and water ceased to distill from solution.The reactor was then heated to 100° C. in vacuo (10 torr abs) and thattemperature was maintained until the 2-ethylhexanol ceased to distillfrom solution. The remaining material was then distilled using a Myers15 Centrifugal Distillation still at 200° C. under an absolute pressureof approximately 12 microns (0.012 torr) to remove all monoestermaterial leaving behind estolides (Ex. 1). Certain data are reportedbelow in Tables 1 and 8.

Example 2

The acid catalyst reaction was conducted in a 50 gallon PfaudlerRT-Series glass-lined reactor. Oleic acid (50 Kg, OL 700, Twin Rivers)and whole cut coconut fatty acid (18.754 Kg, TRC 110, Twin Rivers) wereadded to the reactor with 70% perchloric acid (1145 mL, AldrichCat#244252) and heated to 60° C. in vacuo (10 torr abs) for 24 hrs whilecontinuously being agitated. After 24 hours the vacuum was released.2-Ethylhexanol (34.58 Kg) was then added to the reactor and the vacuumwas restored. The reaction was allowed to continue under the sameconditions (60° C., 10 torr abs) for 4 more hours. At which time, KOH(744.9 g) was dissolved in 90% ethanol/water (5000 mL, 90% EtOH byvolume) and added to the reactor to quench the acid. The solution wasthen allowed to cool for approximately 30 minutes. The contents of thereactor were then pumped through a 1μ filter into an accumulator tofilter out the salts. Water was then added to the accumulator to washthe oil. The two liquid phases were thoroughly mixed together forapproximately 1 hour. The solution was then allowed to phase separatefor approximately 30 minutes. The water layer was drained and disposedof. The organic layer was again pumped through a 1μ filter back into thereactor. The reactor was heated to 60° C. in vacuo (10 torr abs) untilall ethanol and water ceased to distill from solution. The reactor wasthen heated to 100° C. in vacuo (10 torr abs) and that temperature wasmaintained until the 2-ethylhexanol ceased to distill from solution. Theremaining material was then distilled using a Myers 15 CentrifugalDistillation still at 200° C. under an absolute pressure ofapproximately 12 microns (0.012 torr) to remove all monoester materialleaving behind estolides (Ex. 2). Certain data are reported below inTables 2 and 7.

Example 3

The estolides produced in Example 1 (Ex. 1) were subjected todistillation conditions in a Myers 15 Centrifugal Distillation still at300° C. under an absolute pressure of approximately 12 microns (0.012torr). This resulted in a primary distillate having a lower EN average(Ex. 3A), and a distillation residue having a higher EN average (Ex.3B). Certain data are reported below in Tables 1 and 8.

TABLE 1 Pour Iodine Estolide Point Value Base Stock EN (° C.) (cg/g) Ex.3A 1.35 −32 31.5 Ex. 1 2.34 −40 22.4 Ex. 3B 4.43 −40 13.8

Example 4

Estolides produced in Example 2 (Ex. 2) were subjected to distillationconditions in a Myers 15 Centrifugal Distillation still at 300° C. underan absolute pressure of approximately 12 microns (0.012 torr). Thisresulted in a primary distillate having a lower EN average (Ex. 4A), anda distillation residue having a higher EN average (Ex. 4B). Certain dataare reported below in Tables 2 and 7.

TABLE 2 Estolide Iodine Base Stock EN Pour Point (° C.) Value (cg/g) Ex.4A 1.31 −30 13.8 Ex. 2 1.82 −33 13.2 Ex. 4B 3.22 −36 9.0

Example 5

Estolides produced by the method set forth in Example 1 were subjectedto distillation conditions (ASTM D-6352) at 1 atm over the temperaturerange of about 0° C. to about 710° C., resulting in 10 differentestolide cuts recovered at increasing temperatures The amount ofmaterial distilled from the sample in each cut and the temperature atwhich each cut distilled (and recovered) are reported below in Table 3:

TABLE 3 Cut (% of total) Temp. (° C.) 1 (1%)  416.4 2 (1%)  418.1 3(3%)  420.7 4 (20%) 536.4 5 (25%) 553.6 6 (25%) 618.6 7 (20%) 665.7 8(3%)  687.6 9 (1%)  700.6 10 (1%)  709.1

Example 6

Estolides made according to the method of Example 2 were subjected todistillation conditions (ASTM D-6352) at 1 atm over the temperaturerange of about 0° C. to about 730° C., which resulted in 10 differentestolide cuts. The amount of each cut and the temperature at which eachcut was recovered are reported in Table 4.

TABLE 4 Cut (% of total) Temp. (° C.) 1 (1%) 417.7 2 (1%) 420.2 3 (3%)472.0 4 (5%) 509.7  5 (15%) 533.7  6 (25%) 583.4  7 (25%) 636.4 8 (5%)655.4 9 (5%) 727.0 10 (15%) >727.0

Example 7

Estolide base oil 4B (from Example 4) was subjected to distillationconditions (ASTM D-6352) at 1 atm over the temperature range of about 0°C. to about 730° C., which resulted in 9 different estolide cuts. Theamount of each cut and the temperature at which each cut was recoveredare reported in Table 5a.

TABLE 5a Cut (% of total) Temp. (° C.) 1 (1%) 432.3 2 (1%) 444.0 3 (3%)469.6 4 (5%) 521.4  5 (15%) 585.4  6 (25%) 617.1  7 (25%) 675.1 8 (5%)729.9  9 (20%) >729.9

Example 8

Estolides were made according to the method set forth in Example 1,except that the 2-ethylhexanol esterifying alcohol used in Example 1 wasreplaced with various other alcohols. Alcohols used for esterificationinclude those identified in Table 5b below. The properties of theresulting estolides are set forth in Table 9.

TABLE 5b Alcohol Structure Jarcol ™ I-18CG iso-octadecanol Jarcol ™ I-122-butyloctanol Jarcol ™ I-20 2-octyldodecanol Jarcol ™ I-162-hexyldecanol Jarcol ™ 85BJ cis-9-octadecen-1-ol Fineoxocol ® 180

Jarcol ™ I-18T 2-octyldecanol

Example 9

Estolides were made according to the method set forth in Example 2,except the 2-ethylhexanol esterifying alcohol was replaced withisobutanol. The properties of the resulting estolides are set forth inTable 9.

Example 10

Estolides of Formula I, II, and III are prepared according to the methodset forth in Examples 1 and 2, except that the 2-ethylhexanolesterifying alcohol is replaced with various other alcohols. Alcohols tobe used for esterification include those identified in Table 6 below.Esterifying alcohols to be used, including those listed below, may besaturated or unsaturated, and branched or unbranched, or substitutedwith one or more alkyl groups selected from methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl,neopentyl, hexyl, isohexyl, and the like, to form a branched orunbranched residue at the R₂ position. Examples of combinations ofesterifying alcohols and R₂ Substituents are set forth below in Table 6:

TABLE 6 Alcohol R₂ Substituents C₁ alkanol methyl C₂ alkanol ethyl C₃alkanol n-propyl, isopropyl C₄ alkanol n-butyl, isobutyl, sec-butyl C₅alkanol n-pentyl, isopentyl neopentyl C₆ alkanol n-hexyl, 2-methylpentyl, 3- methyl pentyl, 2,2-dimethyl butyl, 2,3-dimethyl butyl C₇alkanol n-heptyl and other structural isomers C₈ alkanol n-octyl andother structural isomers C₉ alkanol n-nonyl and other structural isomersC₁₀ alkanol n-decanyl and other structural isomers C₁₁ alkanoln-undecanyl and other structural isomers C₁₂ alkanol n-dodecanyl andother structural isomers C₁₃ alkanol n-tridecanyl and other structuralisomers C₁₄ alkanol n-tetradecanyl and other structural isomers C₁₅alkanol n-pentadecanyl and other structural isomers C₁₆ alkanoln-hexadecanyl and other structural isomers C₁₇ alkanol n-heptadecanyland other structural isomers C₁₈ alkanol n-octadecanyl and otherstructural isomers C₁₉ alkanol n-nonadecanyl and other structuralisomers C₂₀ alkanol n-icosanyl and other structural isomers C₂₁ alkanoln-heneicosanyl and other structural isomers C₂₂ alkanol n-docosanyl andother structural isomers

TABLE 7 ASTM PROPERTY ADDITIVES METHOD Ex. 4A Ex. 2 Ex. 4B Color None —Light Gold Amber Amber Specific Gravity (15.5° C.), g/ml None D 4052 n/a(<1) 0.9046 0.9140 Viscosity - Kinematic at 40° C., cSt None D 445 32.565.4 137.3 Viscosity - Kinematic at 100° C., cSt None D 445 6.8 11.319.9 Viscosity Index None D 2270 175 167 167 Pour Point, ° C. None D 97−30 −33 −36 Cloud Point, ° C. None D 2500 −30 −32 −36 Flash Point, ° C.None D 92 n/a n/a n/a (>286) (>200) (>250) Evaporative Loss (NOACK), wt.% None D 5800 n/a 1.4 0.32 Vapor Pressure - Reid (RVP), psi None D 5191≈0 ≈0 ≈0

TABLE 8 ASTM PROPERTY ADDITIVES METHOD Ex. 3A Ex. 1 Ex. 3B Color None —Light Gold Amber Amber Specific Gravity (15.5° C.), g/ml None D 4052 n/a(<1) 0.906 n/a (<1) Viscosity - Kinematic at 40° C., cSt None D 445 40.991.2 211.6 Viscosity - Kinematic at 100° C., cSt None D 445 8.0 14.827.8 Viscosity Index None D 2270 172 170 169 Pour Point, ° C. None D 97−32 −40 −40 Cloud Point, ° C. None D 2500 −32 −33 −40 Flash Point, ° C.None D 92 n/a 286 n/a (>286) (>200) Evaporative Loss (NOACK), wt. % NoneD 5800 n/a 0.8 n/a (<0.3) Vapor Pressure - Reid (RVP), psi None D 5191≈0 ≈0 ≈0

TABLE 9 Ex- Estimated Pour Cloud Visc. Visc. ample EN Pt. Pt. @ @ Vis. #Alcohol (approx.) ° C. ° C. 40° C. 100° C. Index 8 Jarcol ™ 2.0-2.6 −15−13 103.4 16.6 174 I-18CG 8 Jarcol ™ 2.0-2.6 −39 −40 110.9 16.9 166 I-128 Jarcol ™ 2.0-2.6 −42 <−42 125.2 18.5 166 I-20 8 Jarcol ™ 2.0-2.6 −51<−51 79.7 13.2 168 I-16 8 Jarcol ™ 2.0-2.6 −15 −6 123.8 19.5 179 85BJ 8Fineoxocol ® 2.0-2.6 −39 −41 174.2 21.1 143 180 8 Jarcol ™ 2.0-2.6 −42<−42 130.8 19.2 167 I-18T 8 Isobutanol 2.0-2.6 −36 −36 74.1 12.6 170 9Isobutanol 1.5-2.2 −36 −36 59.5 10.6 170

Example 11

Saturated and unsaturated estolides having varying acid values weresubjected to several corrosion and deposit tests. These tests includedthe High Temperature Corrosion Bench Test (HTCBT) for several metals,the ASTM D130 corrosion test, and the MHT-4 TEOST (ASTM D7097) test forcorrelating piston deposits. The estolides tested having higher acidvalues (0.67 mg KOH/g) were produced using the method set forth inExamples 1 and 4 for producing Ex. 1 and Ex. 4A (Ex.1* and Ex.4A*below). The estolides tested having lower acid values (0.08 mg KOH/g)were produced using the method set forth in Examples 1 and 4 forproducing Ex. 1 and Ex. 4A except the crude free-acid estolide wasworked up and purified prior to esterification with BF₃.OET₂ (0.15equiv.; reacted with estolide and 2-EH in Dean Stark trap at 80° C. invacuo (10 torr abs) for 12 hrs while continuously being agitated; crudereaction product washed 4× H₂O; excess 2-EH removed by heating washedreaction product to 140° C. in vacuo (10 torr abs) for 1 hr) (Ex.4A#below). Estolides having an IV of 0 were hydrogenated via 10 wt. %palladium embedded on carbon at 75° C. for 3 hours under a pressurizedhydrogen atmosphere (200 psig) (Ex.4A*H and Ex.4A#H below) The corrosionand deposit tests were performed with a Dexos™ additive package. Resultswere compared against a mineral oil standard:

TABLE 10 Ex. Ex. Ex. Ex. Ex. 1* 4A* 4A*H 4A# 4A#H Standard EstolideEstolide Estolide Estolide Estolide Acid Value — ~0.7 0.67 0.67 0.080.08 (mg KOH/g) Iodine Value — ~45 16 0 16 0 (IV) HTCBT Cu 13 739 279 609.3 13.6 HTCBT Pd 177 11,639 1,115 804 493 243 HTCBT Sn 0 0 0 0 0 0 ASTMD130 1A 4B 3A 1B 1A 1A MHT-4 18 61 70 48 12 9.3

Example 12

“Ready” and “ultimate” biodegradability of the estolide produced in Ex.1 was tested according to standard OECD procedures. Results of the OECDbiodegradability studies are set forth below in Table 11:

TABLE 11 301D 28-Day 302D Assay (% degraded) (% degraded) Canola Oil86.9 78.9 Ex. 1 64.0 70.9 Base Stock

Example 13

The Ex. 1 estolide base stock from Example 1 was tested under OECD 203for Acute Aquatic Toxicity. The tests showed that the estolides arenontoxic, as no deaths were reported for concentration ranges of 5,000mg/L and 50,000 mg/L.

The invention claimed is:
 1. A composition comprising two or moreestolide compounds, said composition having: an EN selected from aninteger or fraction of an integer that is equal to or greater than 4,wherein the EN is the average number of estolide linkages in compoundsaccording to Formula I; a kinematic viscosity equal to or greater than200 cSt when measured at 40° C.; and a pour point equal to or lower than−40° C., wherein said two or more estolide compounds are selected fromcompounds of Formula I:

wherein x is, independently for each occurrence, an integer selectedfrom 0 to 20; y is, independently for each occurrence, an integerselected from 0 to 20; n is an integer selected from 0 to 12; R₁ is anoptionally substituted alkyl that is saturated or unsaturated, andbranched or unbranched; and R₂ is an optionally substituted alkyl thatis saturated or unsaturated, and branched or unbranched, wherein eachfatty acid chain residue of said two or more estolide compounds isindependently optionally substituted.
 2. The composition according toclaim 1, wherein x is, independently for each occurrence, an integerselected from 1 to 10; y is, independently for each occurrence, aninteger selected from 1 to 10; n is an integer selected from 0 to 8; R₁is an optionally substituted C₁ to C₂₂ alkyl that is saturated orunsaturated, and branched or unbranched; and R₂ is an optionallysubstituted C₁ to C₂₂ alkyl that is saturated or unsaturated, andbranched or unbranched, wherein each fatty acid chain residue isunsubstituted.
 3. The composition according to claim 1, wherein x+y is,independently for each fatty acid chain residue, an integer selectedfrom 13 to 15; and n is an integer selected from 0 to
 6. 4. Thecomposition according to claim 1, wherein x+y is 15 for at least onefatty acid chain residue.
 5. The composition according to claim 1,wherein R₂ is a branched or unbranched C₁ to C₂₀ alkyl that is saturatedor unsaturated.
 6. The composition according to claim 5, wherein R₂ isselected from methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,octyl, nonyl, decanyl, undecanyl, dodecanyl, tridecanyl, tetradecanyl,pentadecanyl, hexadecanyl, heptadecanyl, octadecanyl, nonadecanyl, andicosanyl, which are saturated or unsaturated and branched or unbranched.7. The composition according to claim 1, wherein R₂ is selected from C₆to C₁₂ alkyl.
 8. The composition according to claim 7, wherein R₂ is2-ethylhexyl.
 9. The composition according to claim 1, wherein R₁ isselected from unsubstituted C₇ to C₁₇ alkyl that is unbranched andsaturated or unsaturated.
 10. The composition according to claim 1,wherein R₁ is selected from C₁₃ to C₁₇ alkyl that is unsubstituted,unbranched, and saturated or unsaturated.
 11. The composition accordingto claim 10, wherein R₁ is selected from saturated C₁₃ alkyl, saturatedC₁₅ alkyl, and saturated or unsaturated C₁₇ alkyl, which areunsubstituted and unbranched.
 12. The composition according to claim 1,wherein R₁ and R₂ are independently selected from optionally substitutedC₁ to C₁₈ alkyl that is saturated or unsaturated, and branched orunbranched.
 13. The composition according to claim 1, wherein R₁ isselected from optionally substituted C₇ to C₁₇ alkyl that is saturatedor unsaturated, and branched or unbranched; and R₂ is selected from anoptionally substituted C₃ to C₂₀ alkyl that is saturated or unsaturated,and branched or unbranched.
 14. The composition according to claim 1,wherein said composition has an EN that is an integer or fraction of aninteger selected from 4 to
 5. 15. The composition according to claim 14,wherein said composition has an EN that is a fraction of an integerselected from 4.2 to 4.8.
 16. The composition according to claim 1,wherein said composition has an EN selected from an integer or fractionof an integer that is equal to or greater than
 5. 17. The compositionaccording to claim 1, wherein said composition has a kinematic viscosityof 200 cSt to 250 cSt at 40° C.
 18. The composition according to claim17, wherein said composition has a kinematic viscosity of 210 cSt to 230cSt at 40° C.
 19. The composition according to claim 1, wherein saidcomposition has a pour point of −40° C. to −50° C.
 20. The compositionaccording to claim 19, wherein said composition has a pour point of −42°C. to −48° C.
 21. The composition according to claim 1, wherein saidcomposition has a pour point of less than −50° C.
 22. The compositionaccording to claim 21, wherein said composition has a pour point of −50°C. to −60° C.
 23. The composition according to claim 21, wherein saidcomposition has a pour point of −52° C. to −58° C.
 24. The compositionaccording to claim 1, wherein said composition exhibits an iodine value(IV) of less than 15 cg/g.
 25. The composition according to claim 24,wherein said composition exhibits an iodine value (IV) of less than 10cg/g.
 26. The composition according to claim 1, wherein said compositionconsists essentially of the two or more estolide compounds of Formula I.27. The composition according to claim 1, wherein R₂ is an unsubstitutedalkyl that is saturated or unsaturated, and branched or unbranched. 28.The composition according to claim 1, wherein R₁ is an unsubstitutedalkyl that is saturated or unsaturated, and branched or unbranched. 29.The composition according to claim 1, wherein R₁ is optionallysubstituted with a group that is not hydroxyl.
 30. The compositionaccording to claim 1, wherein said two or more estolide compounds arederived from a process that comprises forming a covalent bond between anoxygen of a carboxylic group of at least one first fatty acid and acarbon of at least one site of unsaturation of at least one second fattyacid.